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Field Performance of a Ground-Coupled Heat Pump in Abilene, Texas
Abstract
A nominal 10.6 kW (3 ton), vertical-configuration
ground-coupled heat pump was
installed in Abilene, Texas in December 1989
and was monitored until May 1993 using a
remote data acquisition system. The unit was
installed in the guest officer quarters at Dyes
Air Force Base. Monitored data included:
temperature and relative humidity of return and
supply air, water temperature entering and
leaving the condenser, power consumption of
the individual system components, cycling rate,
on-time, and soil temperatures at various depths
and radial locations. Water and air flow rates
were measured twice during the monitored
period, and have remained constant. The
measured quantities allow calculation of
instantaneous capacity, power, coefficient of
performance (COP), and ground-coil heat
rejection.
Data for operation in the cooling and
heating mode are discussed here. Based on the
experimental data, it was discovered that the
water temperature entering the condenser
(EWT) exhibited a prolonged minimum after
start-up due to cooling of the water during the
off-cycle when operating in the cooling mode.
The decreased levels of EWT early in the cycle
increased capacity and decreased power, both acting to increase the COP. Seasonal COPs for heating and cooling were estimated from the data and are presented.
Citation
Dobson, M.; O'Neal, D. L.; Aldred, W.; Margo, R. (1994). Field Performance of a Ground-Coupled Heat Pump in Abilene, Texas. Energy Systems Laboratory (http://esl.tamu.edu); Texas A&M University (http://www.tamu.edu). Available electronically from https : / /hdl .handle .net /1969 .1 /6649.